Embodiments herein generally relate to electrostatographic printers and copiers or reproduction machines, and more particularly, concerns an air knife used to lift media off heating devices such as fusers that has the ability to rotate.
In a typical electrophotographic printing process, a photoconductive member is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charges thereon in the irradiated areas. This records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles are attracted from the carrier granules to the latent image forming a toner powder image on the photoconductive member. The toner powder image is then transferred from the photoconductive member to a copy sheet. The toner particles are heated or fused to permanently affix the powder image to the copy sheet.
The foregoing generally describes a typical black and white electrophotographic printing machine. With the advent of multicolor electrophotography, it is desirable to use an architecture which comprises a plurality of image forming stations. One example of the plural image forming station architecture utilizes an image-on-image (IOI) system in which the photoreceptive member is recharged, reimaged and developed for each color separation. This charging, imaging, developing and recharging, reimaging and developing, all followed by transfer to paper, is done in a single revolution of the photoreceptor in so-called single pass machines, while multipass architectures form each color separation with a single charge, image and develop, with separate transfer operations for each color.
In addition, as described in U.S. Pat. No. 6,385,405, the complete disclosure of which is incorporated herein by reference, direct marking technologies, and in particular ink jet printing, have emerged as printing alternatives that incorporate relatively simpler hardware requirements. However, images produced with the inks used in ink jet marking technologies, and particularly in thermal ink jet marking technologies, do not always exhibit the same high level of clarity or permanence as xerographically produced images. Therefore, as described in U.S. Pat. No. 6,385,405, ink jet printing can be combined with electrophotographic printing to fuse the ink onto the page.
In direct marking technologies, ink in the desired image is applied directly to the print medium. Various techniques of direct marking are well understood in the art. For example, the image may be applied by direct contact between a pen and the medium. Alternatively, ink jet recording techniques eject droplets of ink from a printhead onto the medium. Such ink jet techniques may include thermal ink jets, acoustic ink jet, piezo-electric ink jet printing, and others. Ink jet recording devices eject ink onto a print medium such as paper in controlled patterns of closely spaced dots. To form color images, multiple groupings of ink jets are used, with each group being supplied with ink of a different color from an associated ink container.
When performing the fusing of the image onto the sheet, a fuser typically fixes the toner layer with the embedded image onto the surface of the print medium. The fuser may be of the type conventionally used with xerographic printers. For example, the fuser may include a fuser roller and a pressure roller. The fuser roller may be heated to melt the toner, while the pressure roller presses the print medium against the fuser roller. The fuser roller may also be unheated. Those familiar with the xerographic printing arts will recognize that radiant fusing may also be used. Radiant fusing systems use intense light, such as a quartz rod to melt the toner and fuse it with the fibers of the paper. Those skilled in the art will also recognize that other fusing mechanisms used in the xerographic printing art may also be used.